PROBLEM TO BE SOLVED: To obtain wire-shaped welded parts which have high quality and are strong to fatigue strength, bending and stretching by regulating the energy value of spot welding to a specific value at the time of butting the ends of flexible pipes against each other and welding these sends by irradiating the outer periphery thereof with a laser spot. SOLUTION: The flexible pipes 1, 2 are respectively fixed to rotary chucks and the end faces 3, 4 of the flexible pipes 1, 2 are pressed by, for example, load of 100g weight. While the flexible pipes 1, 2 are rotated at a specified angle in this sate at every one spot of the laser beam 10, the end faces 3 and 4 of the butt parts are spot welded by the laser beam 10. At this time, energy value of the spot welding is set at the energy value at which the end faces 3, 4 of the butt parts of the flexible pipes 1, 2 are not welded unless the clearance therebetween is =0.01mm or at the energy value of =0.1mm in the thickness of the heat affected zone generated by the spot welding. The welding is executed =2 rounds by setting the rotating quantity of the flexible pipes 1, 2 to be rotated at every spot of the laser beam 10 in such a manner that the overlap of the adjacent laser spot traces attains 10%.
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